Griefing yourself by using less effective weapons or "not cheap" weapons is only advisable if you can be happy with the feeling of superiority that you get from it. If it's not enough then you have to find a game where it's fair, or where the developers make maps bigger than shoe boxes. People who complain about the SMGs, or the 870, or the Target Finder or whatever either need to get enough satisfaction that they are good enough not to use it, or they need to do something productive. If you seriously think it ruins the game then don't yell at the people, tell the developers for christ's sake.
I personally felt the exact same way all through to this game, I refused to use the M16 in CoD4, I refused to use the Famas/Scar in MW2 (stopped playing before OMA problem), and wouldn't use the Famas in Blops 1. (didn't play MW3).
But in this game, the connections are so bad that it doesn't matter what I use, either I'll do amazing with any gun or I'll struggle to break even K/D wise with the best guns. So I've thrown out the window any semblance of a fair game and merely challenge myself. If it's a good connection, I'll use the Ballista, if it's a bad connection, I'll use the Select fire FAL and still struggle because I rush. I use C-4 for those campers too, I'm not ashamed. In the end the only person you are accountable to is you.